The present invention is directed to a method and apparatus for cleaning, disinfecting and sterilizing medical instruments and particulary for cleaning disinfecting and sterilizing dental instruments.
From a hygenic point of view, the instruments such as forceps, tweezers, dental drills and etc. used in medical or respectively dental treatment should be germ-free. In order to meet this demand, it is normal to usually clean the instruments after their use by means of an ultrasonic cleaning system and examples of these systems are disclosed in U.S. Pat. Nos. 3,007,479 and 3,640,295. Then after cleaning, the instruments are disinfected or respectively sterilized in further or addtional work steps. The disinfection is usually carried out by a chemical solutions such as alchohols or fenols whereas hot air at about 180.degree.-200.degree. C. or superheated steam are utilized for the sterilization.
Instruments or part of instruments of non-metallic material, in particular, do not withstand these relatively high thermal stresses during sterilization. So-called gas sterilizers which utilize ethylene oxide are used in order to sterilize these sensitive instruments in a gentle way. A disadvantage of utilizing ethylene oxide is that it requires a relatively long sterilizing time of a number of hours and ethylene oxide is highly toxic, explosive and, thus, a fire hazard. Thus, the use of ethylene oxide will require a relatively high cost for the necessary safety precautions.